diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index e5de38c482..973d86e9ce 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -205,7 +205,7 @@ public:
 Buffer::Impl::Impl(Buffer & parent, FileName const & file, bool readonly_)
 	: lyx_clean(true), bak_clean(true), unnamed(false), read_only(readonly_),
 	  filename(file), file_fully_loaded(false), inset(params),
-	  timestamp_(0), checksum_(0), toc_backend(&parent)
+	  toc_backend(&parent), timestamp_(0), checksum_(0)
 {
 	inset.setAutoBreakRows(true);
 	lyxvc.buffer(&parent);
diff --git a/src/ToolbarBackend.cpp b/src/ToolbarBackend.cpp
index c6f78f61ed..8baddc4f54 100644
--- a/src/ToolbarBackend.cpp
+++ b/src/ToolbarBackend.cpp
@@ -63,7 +63,7 @@ ToolbarItem::ToolbarItem(Type type, FuncRequest const & func, docstring const &
 
 
 ToolbarItem::ToolbarItem(Type type, string const & name, docstring const & label)
-	: type_(type), name_(name), label_(label)
+	: type_(type), label_(label), name_(name)
 {
 }
 
diff --git a/src/mathed/InsetMath.h b/src/mathed/InsetMath.h
index eaf6a40af9..3226d13111 100644
--- a/src/mathed/InsetMath.h
+++ b/src/mathed/InsetMath.h
@@ -63,7 +63,6 @@ class InsetMathGrid;
 class InsetMathHull;
 class InsetMathMatrix;
 class InsetMathNest;
-class InsetMathParbox;
 class InsetMathScript;
 class InsetMathString;
 class InsetMathSpace;
@@ -132,7 +131,6 @@ public:
 	virtual InsetMathMatrix const   * asMatrixInset() const   { return 0; }
 	virtual InsetMathNest           * asNestInset()           { return 0; }
 	virtual InsetMathNest const     * asNestInset() const     { return 0; }
-	virtual InsetMathParbox         * asParboxInset()         { return 0; }
 	virtual InsetMathScript         * asScriptInset()         { return 0; }
 	virtual InsetMathScript const   * asScriptInset() const   { return 0; }
 	virtual InsetMathSpace          * asSpaceInset()          { return 0; }
diff --git a/src/mathed/InsetMathGrid.cpp b/src/mathed/InsetMathGrid.cpp
index a3b680dd34..0a62b19cab 100644
--- a/src/mathed/InsetMathGrid.cpp
+++ b/src/mathed/InsetMathGrid.cpp
@@ -178,6 +178,7 @@ void InsetMathGrid::setDefaults()
 	for (col_type col = 0; col < ncols(); ++col) {
 		colinfo_[col].align_ = defaultColAlign(col);
 		colinfo_[col].skip_  = defaultColSpace(col);
+		colinfo_[col].special_.clear();
 	}
 }
 
@@ -189,13 +190,70 @@ void InsetMathGrid::halign(docstring const & hh)
 		char_type c = *it;
 		if (c == '|') {
 			colinfo_[col].lines_++;
+		} else if ((c == 'p' || c == 'm' || c == 'b'||
+		            c == '!' || c == '@' || c == '>' || c == '<') &&
+		           it + 1 != hh.end() && *(it + 1) == '{') {
+			// @{decl.} and p{width} are standard LaTeX, the
+			// others are extensions by array.sty
+			bool const newcolumn = c == 'p' || c == 'm' || c == 'b';
+			if (newcolumn) {
+				// this declares a new column
+				if (col >= ncols())
+					// Only intercolumn stuff is allowed
+					// in the last dummy column
+					break;
+				colinfo_[col].align_ = 'l';
+			} else {
+				// this is intercolumn stuff
+				if (colinfo_[col].special_.empty())
+					// Overtake possible lines
+					colinfo_[col].special_ = docstring(colinfo_[col].lines_, '|');
+			}
+			int brace_open = 0;
+			int brace_close = 0;
+			while (it != hh.end()) {
+				c = *it;
+				colinfo_[col].special_ += c;
+				if (c == '{')
+					++brace_open;
+				else if (c == '}')
+					++brace_close;
+				++it;
+				if (brace_open > 0 && brace_open == brace_close)
+					break;
+			}
+			--it;
+			if (newcolumn) {
+				colinfo_[col].lines_ = std::count(
+					colinfo_[col].special_.begin(),
+					colinfo_[col].special_.end(), '|');
+				LYXERR(Debug::MATHED)
+					<< "special column separator: `"
+					<< to_utf8(colinfo_[col].special_)
+					<< '\'' << endl;
+				++col;
+				colinfo_[col].lines_ = 0;
+				colinfo_[col].special_.clear();
+			}
 		} else if (col >= ncols()) {
-			// Only '|' is allowed in the last dummy column
+			// Only intercolumn stuff is allowed in the last
+			// dummy column
 			break;
 		} else if (c == 'c' || c == 'l' || c == 'r') {
-			colinfo_[col].align_ = (char)c;
+			colinfo_[col].align_ = static_cast<char>(c);
+			if (!colinfo_[col].special_.empty()) {
+				colinfo_[col].special_ += c;
+				colinfo_[col].lines_ = std::count(
+						colinfo_[col].special_.begin(),
+						colinfo_[col].special_.end(), '|');
+				LYXERR(Debug::MATHED)
+					<< "special column separator: `"
+					<< to_utf8(colinfo_[col].special_)
+					<< '\'' << endl;
+			}
 			++col;
 			colinfo_[col].lines_ = 0;
+			colinfo_[col].special_.clear();
 		} else {
 			lyxerr << "unknown column separator: '" << c << "'" << endl;
 		}
@@ -215,7 +273,8 @@ InsetMathGrid::col_type InsetMathGrid::guessColumns(docstring const & hh) const
 {
 	col_type col = 0;
 	for (docstring::const_iterator it = hh.begin(); it != hh.end(); ++it)
-		if (*it == 'c' || *it == 'l' || *it == 'r')
+		if (*it == 'c' || *it == 'l' || *it == 'r'||
+		    *it == 'p' || *it == 'm' || *it == 'b')
 			++col;
 	// let's have at least one column, even if we did not recognize its
 	// alignment
@@ -228,6 +287,12 @@ InsetMathGrid::col_type InsetMathGrid::guessColumns(docstring const & hh) const
 void InsetMathGrid::halign(char h, col_type col)
 {
 	colinfo_[col].align_ = h;
+	if (!colinfo_[col].special_.empty()) {
+		char_type & c = colinfo_[col].special_[colinfo_[col].special_.size() - 1];
+		if (c == 'l' || c == 'c' || c == 'r')
+			c = h;
+	}
+	// FIXME: Change alignment of p, m and b columns, too
 }
 
 
@@ -241,10 +306,15 @@ docstring InsetMathGrid::halign() const
 {
 	docstring res;
 	for (col_type col = 0; col < ncols(); ++col) {
-		res += docstring(colinfo_[col].lines_, '|');
-		res += colinfo_[col].align_;
+		if (colinfo_[col].special_.empty()) {
+			res += docstring(colinfo_[col].lines_, '|');
+			res += colinfo_[col].align_;
+		} else
+			res += colinfo_[col].special_;
 	}
-	return res + docstring(colinfo_[ncols()].lines_, '|');
+	if (colinfo_[ncols()].special_.empty())
+		return res + docstring(colinfo_[ncols()].lines_, '|');
+	return res + colinfo_[ncols()].special_;
 }
 
 
@@ -1147,14 +1217,34 @@ void InsetMathGrid::doDispatch(Cursor & cur, FuncRequest & cmd)
 			swapCol(cur.col());
 			cur.pos() = 0; // trick, see above
 		}
-		else if (s == "add-vline-left")
+		else if (s == "add-vline-left") {
 			colinfo_[cur.col()].lines_++;
-		else if (s == "add-vline-right")
+			if (!colinfo_[cur.col()].special_.empty())
+				colinfo_[cur.col()].special_ += '|';
+		}
+		else if (s == "add-vline-right") {
 			colinfo_[cur.col()+1].lines_++;
-		else if (s == "delete-vline-left")
+			if (!colinfo_[cur.col()+1].special_.empty())
+				colinfo_[cur.col()+1].special_.insert(0, 1, '|');
+		}
+		else if (s == "delete-vline-left") {
 			colinfo_[cur.col()].lines_--;
-		else if (s == "delete-vline-right")
+			docstring & special = colinfo_[cur.col()].special_;
+			if (!special.empty()) {
+				docstring::size_type i = special.rfind('|');
+				BOOST_ASSERT(i != docstring::npos);
+				special.erase(i, 1);
+			}
+		}
+		else if (s == "delete-vline-right") {
 			colinfo_[cur.col()+1].lines_--;
+			docstring & special = colinfo_[cur.col()+1].special_;
+			if (!special.empty()) {
+				docstring::size_type i = special.find('|');
+				BOOST_ASSERT(i != docstring::npos);
+				special.erase(i, 1);
+			}
+		}
 		else {
 			cur.undispatched();
 			break;
diff --git a/src/mathed/InsetMathGrid.h b/src/mathed/InsetMathGrid.h
index 3faa33f4ea..6d80ad6a4e 100644
--- a/src/mathed/InsetMathGrid.h
+++ b/src/mathed/InsetMathGrid.h
@@ -83,6 +83,11 @@ public:
 		unsigned int lines_;
 		/// additional amount to be skipped when drawing
 		int skip_;
+		/// Special alignment.
+		/// This does also contain align_ and lines_ if it is nonempty.
+		/// It needs to be in sync with align_ and lines_ because some
+		/// code only uses align_ and lines_.
+		docstring special_;
 	};
 
 public:
diff --git a/status.15x b/status.15x
index 50aec41a59..6d56195ba2 100644
--- a/status.15x
+++ b/status.15x
@@ -68,6 +68,9 @@ What's new
 - Conversion from older documents failed if koi8 was used as the
   document encoding (Bug 4158).
 
+- Handle array column specifiers @{decl.}, p{width} and the extenions by
+  array.sty in mathed (Bug 4132).
+
 * USER INTERFACE:
 
 - Fix crash when clicking in a tabular cell and the "delete empty paragraph"